Patent Application
20100005736
This invention relates to construction of buildings using concrete forms. More particularly, this invention relates to a system adapted to temporarily carry a structural load of a building during construction, while the concrete cures, such that construction is not limited by the cure time of concrete components.
Concrete forms for a concrete structure, such as concrete walls, are well known in the construction industry. Such forms are often referred to as Insulating Concrete Forms (or “ICFs”), and hold the shape of the concrete while it cures. Typically, opposing panels of Styrofoam® (Dow Chemical Co.), or other insulating foam panels are interconnected by braces that maintain proper spacing between the panels and maintain the desired form for the concrete structure while the concrete is placed and cured. The braces of opposing panels may also provide support for positioning rebar or other reinforcing materials between the panels while the concrete is being placed and is hardening. Although such foam panels with bracing are typically used, the panels could not independently support construction on a floor above while the concrete wall is being placed and cured.
A series of vertical wall braces, referred to as “stiffbacks,” are typically placed on one or both sides of the concrete forms, secured to a base, and attached to the concrete forms to provide lateral support to the concrete forms during and/or after the concrete is placed. Diagonal braces also may be attached to an upper portion of the vertical wall braces to provide additional lateral support. Brackets or other similar structures may also be attached to the vertical braces near the top of the concrete forms to provide workers with access during assembly of the upper portions of the concrete forms and pouring of the concrete.
Once the concrete forms and braces are fully assembled, concrete is placed into the concrete forms and allowed to harden. The stiffbacks and diagonal bracing provided support for the concrete forms while laterally supporting concrete placed and not yet cured. Also, such stiffbacks previously could not provide support for building construction above while supporting the placed, uncured concrete wall.
In the case of multi-story structures, where an open web truss such as a steel truss, a corrugated metal subfloor and a concrete slab were typically assembled and placed for a second or subsequent floor, it was necessary to allow the concrete walls to harden so the concrete walls would provide the structural strength for the construction load of the floor assembly above before the wall braces could be removed and construction of the floor above could proceed. Also, removal of the braces from the walls typically was necessary before a concrete slab could be placed because the braces may extend above the walls and interfered with construction of the floor above. Therefore, the construction of the floor above a concrete wall would typically be separated from the construction of the concrete walls by one or two days, or more, substantially increasing the time and costs required for construction of the building structure. Additionally, the use of worker support and protection systems are typically required for the safety of workers for the installation of trusses and subfloor for the construction of the floor above, which further added to structural support needed from below and added to the time delays caused by curing of the concrete walls.
Therefore, a need exists for a method of construction that provides temporary structural support for construction of a floor above, while concrete supporting walls are being placed and cured to provide permanent support for the building structure.
The present invention provides a significant savings in time and cost in constructing a building structure using concrete forms, and an assembled floor above the walls. Prior systems required concrete to be placed in a concrete form wall system and allowed to cure upon a first day, followed by assembly of trusses and subfloor decking for the floor above on a subsequent day, and placing of a concrete floor on the following day(s). By contrast, the method of constructing a concrete structure provided herein allows the concrete formed walls and floor assembly above the walls to be erected and concrete wall and floor above to be placed on the same day as desired.
A method of constructing a building structure is disclosed which allows construction of a floor or other construction above the wall to proceed while concrete walls are placed and cured. The method includes assembly of a plurality of adjustable braces attached to concrete forms capable of providing structural support for construction above and for an uncured concrete wall in the forms, where each adjustable brace has an elongated first support and an elongated second support dimensioned to enable the first support to slidably engage the second support. The first and second supports may be dimensioned to allow one to be telescoped into at least a portion of the other along their longitudinal length. A plurality of apertures are spaced along both first and second supports to allow the apertures in the first and second supports to align as the first and second support slide relative to each other. The apertures are adapted to accept one or more fasteners to secure the first support and the second support together to form the brace of an adjustable length capable of providing structural support along the length of the brace.
A cap is provided adjacent an end portion of the first support and is adapted to provide support for trusses for a floor above the concrete forms. The adjustable braces assembled with the wall forms are thus able to temporarily provide structural support to enable construction of a floor above to proceed, as well as provide support for placed concrete walls while the concrete cured to become structural bearing components for the building. Typically, the adjustable braces vertically span the concrete forms to provide structural support for the construction of the floor above, usually from the foundation or floor below the concrete forms.
The cap may comprise an upper portion adapted to support the upper chord of a steel truss and a nesting portion capable of allowing an end web portion of the steel truss to be positioned. The upper portion of the cap may have upper support surfaces spaced to support the upper chord of a steel truss and provide for a passage there between of the web of the truss. The cap may also comprise a lower portion dimensioned to engage the first support such as to be received by an end portion of the first support or to receive the end portion of the first support.
The method may also include placing the adjustable brace adjacent concrete forms and then positioning metal trusses on the caps. The method may also include assembling a steel cover, typically of L-shaped metal pieces, over the top and upper edges of the concrete forms. Workers then may fasten subfloor decking to the assembled trusses. The presence of a passage in the cap permits an upper chord to rest on the cap while a web portion of the truss is positioned in a nesting portion from the top chord to a bottom chord of the trusses. The method also comprises placing concrete above the concrete form over the subfloor decking, with the adjustable braces attached to the concrete forms independently supporting the trusses, subfloor decking and the concrete floor. In this embodiment, the adjustable brace system provides a temporary support structure bearing the load of the truss, decking and concrete above the decking as well as lateral support for the ICF, while the concrete in the wall system cures. The adjustable brace system may be removed once the concrete has sufficiently hardened to independently bear the structural load of the building.
An adjustable brace system for insulating concrete forms is also disclosed comprising a first support, a second support, and a cap. The first and second supports are dimensioned such that the first support slidably engages the second support, or vice versa. The first support may telescope into a portion of the second support, and be capable of providing structural support along the longitudinal length of the adjustable brace. A plurality of apertures is located in the first and second supports to enable the apertures in the first support to align with apertures in the second support and allow adjustment of the length of the adjustable brace. Fasteners such as support pins are inserted into the apertures to secure the first and second supports together and fix the adjustable length of the brace. In one embodiment, the first support and the second support may each comprise a web, a first flange attached to a first edge of the web, and a second flange attached to a second edge of the web, in a generally C-shape cross section. In such an embodiment, the plurality of apertures may be located along the first and second flanges of the first and second supports.
The cap is adapted to be positioned adjacent the end portion of the first support and support a truss in position for a floor structure above. The cap may provide at least one support surface adapted to support one or more chords of a steel truss, with a nesting portion to allow a web portion of a truss to pass through, so that the truss is supported in structural position to support subfloor decking. The cap may comprise an upper portion to provide support for the chord of a truss, with a nesting portion through which a web of the truss may extend, to position the truss for construction of a floor above the concrete wall forms and wall structure. The cap may additionally comprise a lower portion connected to an end portion of the first support of the adjustable brace and a stop, for example in the form of a plate, positioned between the upper portion of the cap and the lower portion of the cap. The stop may have a length and width greater than the dimensions of the first or second support. The stop may additionally contain a gap that communicates to provide for positioning of a truss positioned for construction of a floor structure above the concrete wall forms and wall structure.
The lower cap portion may additionally comprise one or more reinforcing members extending from a first flange of the lower cap portion to a second flange of the lower cap portion. The first flange and the second flange of the lower cap portion may additionally comprise one or more apertures. The first support may additionally comprise one or more apertures located in each flange in such a way as to allow apertures in the first support to align with apertures in the lower cap portion, and adapted to accept a pin, a bolt or another type of fastener to secure the first support and the lower cap portion together. Where the first and second supports each comprise a web and first and second flanges attached to opposing edges of the web, as described above, the lower portion of the cap may also comprise a web, a first flange attached to a first edge of the web, and a second flange attached to a second edge of the web, providing a bottom portion for the cap that is C-shaped in cross-section. In any event, the lower cap portion is dimensioned to be insertable into or to otherwise engage the first support.
A method of constructing a concrete structure with adjustable brace system 10 is generally described with reference to
During or after the concrete forms have reached a desired height, adjustable brace systems 10 comprising a first support 12 and a second support 14 are placed adjacent to concrete forms 11. The adjustable brace system 10 may span the length of the assembled courses of the concrete forms 11 and be secured to the foundation or lower floor 13. The adjustable braces are attached to the concrete forms 11 through apertures 38 and 46 in the web of first and/or second supports 12, 14 as described more fully below. Where concrete forms 11 may have pre-placed ties for attachment of the wall brace, those ties may be utilized for this purpose. Although the adjustable brace systems 10 may be positioned at any angle as desired, it may be installed to provide a vertical structural support for the floor above as described below.
A diagonal brace 80 may be secured to a first support 12 and extend diagonally to the foundation floor 13, forming an angle between diagonal brace 80 and the floor. In one example, the angle formed is about 60 degrees. Diagonal brace 80 can be secured to first support 12 within a channel 15 of first support 12. Optionally, an attachment system such as that described in U.S. Pat. No. 6,247,273, may be used to attach diagonal brace 80 to first support 12. Diagonal brace 80 can also be used to provide additional lateral support so that the adjustable brace systems 10 are approximately plumb to achieve a vertical position if desired.
Additional brackets 82 may also be attached to adjustable brace 10 for the construction of a platform or scaffold for workers so that the upper courses of concrete forms 11 may be easily accessed during assembly to the desired height and for pouring of the concrete between the forms 11 to form the concrete wall. The adjustable brace systems 10 may be secured with a plurality of fasteners (not shown) to the courses of concrete forms 11 as the courses are placed in position, or secured after all the courses of concrete forms are assembled to the desired height. Typically, the adjustable brace systems are secured after the first few courses of concrete forms 11 are placed in position and then secured to concrete forms as additional courses of the concrete forms are put into position and secured.
Once the full height of concrete forms 11 are in place, a cover may be placed over the top of the concrete forms 11. The cover may be in the form of continuous L-shaped cold-formed steel 83 installed on top of the concrete forms 11, protecting concrete forms 11 and the exterior of the concrete form during construction, as shown in
Each adjustable brace system is described in more detail with reference to
For assembly of each adjustable brace 10, first support 12 contains a plurality of apertures 32, 34, and 36 spaced along each flange 18. As shown in the Figures, these apertures include upper apertures 32 and 34. For example, first upper aperture 32 is located two inches from the top edge of first support 12 and second upper aperture 34 is spaced 6 inches on center from first upper aperture 32. First support 12 also includes a plurality of lower apertures 36 spaced from upper apertures 32, 34. Lower apertures 36 may be spaced 4 inches on center from each other and from the lower end of first support 12. Lower apertures 36 are also each spaced one inch on center from the edge of flange 18 that adjoins web 16.
Web 16 of first support 12 also may contain a plurality of apertures 38, which may be located along the center portion of web 16. In one example, apertures 38 are oval and spaced 4 inches from each other on center. Apertures 38 are generally used to attach wall brace system 10 to the concrete forms 11 as described above.
For assembly of the adjustable brace 10, second support 14 also contains a plurality of apertures as shown in
The web 24 of the second support 14 also may contain apertures 46 similar to apertures 38 in web 16 of the first support 12. As with apertures 38, apertures 46 may be located along the center portions of web 24. For example, apertures 46 may be oval as shown and spaced about 4 inches on centers. Apertures 46 and 38 are configured and spaced as to align with each other to allow first and second supports 12, 14 and the assembled adjustable brace system 10 to be attached to insulating concrete forms 11.
As mentioned above, first support 12 can be slidably engaged with second support 14 such that apertures 36 are aligned with apertures 40, 42, and one or more bolts or pins 56 are inserted through the aligned apertures 36 and 40, 42 to secure the first and second supports 12, 14 to each other, and provide an assembled adjustable brace system 10 capable of providing structural support for construction above as well as for an uncured concrete wall in the forms 11. In this way, the total length of assembled first support 12 and second support 14 can be varied by altering the apertures through which pins 56 are inserted to provide for different desired heights for concrete forms 11. For example, first support 12 may about 8 feet long, and second support 14 may be about 5 feet long. Apertures 36 may be spaced about 4 inches apart on center, and apertures 40, 42 may be spaced about 8 inches apart on center. Assembled first support 12 and second support 14 may thereby be adjusted to provide an adjustable brace between 8 feet 6 inches to 12 feet 2 inches in height. The apertures may for example be spaced the length of the assembled first support 12 and second support 14, and the adjustable brace system 10 may be adjustable in 4 inch increments. It is also envisioned that by altering the placement of the apertures, the length of the adjustable brace system may be adjustable in other increments. Thus, the adjustable brace system 10 is adjustable and capable of providing structural support for construction above and for an uncured concrete wall in the forms 11.
The adjustable brace may also include an anchor unit 48. Each adjustable brace 10 may have an aperture located so as to align with an aperture of the second support and adapted to allow one or more fastening members to be provided for the apertures to secure the second support 14 to the anchor unit. Anchor unit 48 may take the form of an inverted double “T” with a single anchor member 50 and a pair of vertical members 52, extending from anchor member 50, as illustrated in
Each adjustable brace system 10 also includes a cap 60 which is configured to be inserted onto an end of first support 12 opposite from second support 14 (
Workers can access upper portions of the concrete forms for placement of subfloor decking 86 while standing on a scaffold or platform provided by bracket 82. Guard rails 85 may also be placed on the opposite side of insulating concrete forms 11 for worker safety. Once secured, subfloor decking 86 can be used as a working platform for the remainder of the subfloor installation.
Once subfloor decking 86 is installed, reinforcing screws 94, such as Shearflex® screws, or similar fasteners may be installed through subfloor 86, and concrete placed in concrete forms 11 and over subfloor 86. Rebar 96 may optionally be placed in the concrete form 11, in the concrete floor, or both. The adjustable brace systems 10 have the capacity to temporarily support the concrete forms 11 and the subfloor 86, while the concrete is being placed and until the concrete has cured to support the load of the walls, and trusses, decking and the concrete of the floor above.
Cap 60 may comprise an upper portion 62 that provides surfaces 61 for the truss seat 92 of the trusses, and a lower portion 64 that is inserted within channel 15 of first support 12. Upper portion 62 and lower portion 64 of cap 60 are separated by a stop 66, typically in the form of a plate, having a length and width greater than the dimensions of the first support 12 and the adjustable brace 10. For example, stop 66 may be a plate of about 5.5 inches by 3.5 inches in rectangular shape by 0.25 inches in thickness. In addition, stop 66 may also contain a nesting portion or “notch” 63 corresponding in location to the gap portion of the C-shaped top portion that lies between the first lips 20. Nest portions 63 provide passage for the end web of a truss 84. For example, nesting portion 63 may be a notch about 1 to 1.5 inches wide.
Lower portion 64 of cap 60 may be C-shaped corresponding to the C-shaped dimensions of first support 12 except having narrower dimensions, optionally sufficient to provide a friction fit. For example, lower portion 64 may comprise a web 65 having a width of less than about 5 inches, a pair of opposed flanges 67 of a depth of less than about 3 inches. A portion of the C-shape of lower portion 64 may be reinforced by one or more reinforcing members 68, 70 extending from one flange of the C-shape to the other to create a D-shape in one portion of cap 60. Flanges 67 of cap 60 may also contain apertures 72 which are positioned to communicate with apertures 32 and 34 of first support 12. Bolts, pins or other fasteners 71 may be placed through apertures 72, 32, and 34 to secure cap 60 to first support 12.
For example, lower portion 64 of cap 60 may be 9 inches in height. Stiffener 68 may be a plate of 14 or 16 gauge steel having rectangular shape of about 4.5 inches by 2 inches. Apertures 72 may be spaced 6 inches on center.
Upper portion 62 of cap 60 may comprise upper support member 69 capable of supporting a truss seat 92 of a truss 84 and a nesting portion 59. Nesting portion 59 enables a portion of a truss 84, such as an end web 91, to be positioned unimpeded in an assembled position as shown in
It is to be understood that any evident variations of the above described invention fall within the scope of the claimed invention and thus, the selection of specific embodiments can be selected as desired without departing from the spirit of the invention herein disclosed and described.
